The present invention relates generally to flotation reagents and, more particularly, to xanthogen formate flotation reagents useful in the concentration of copper sulfide ores. The invention is carried out by reacting aromatic amines with an excess of alkyl xanthogen formate, in various proportions, to yield a stable composition of unreacted xanthogen formate and a complex mixture of the reaction products.
Alkyl xanthogen formates are defined by the general formula ##STR1##
where R and R' are lower alkyl radicals, generally with 1 to 6 carbon atoms. These compounds have been successfully used as reagents for the flotation of sulfide copper ores for over thirty years (see U.S. Pat. No. 2,412,500, issued Dec. 10, 1946). They are generally referred to as flotation promoters, and are used in conjunction with other well known flotation reagents, e.g. pine oil, methyl isobutyl carbinol (MIBC), lime, cyanide, etc.
Copper sulfide ores are complex, both physically and chemically, and they are quite variable, even on a day-to-day basis from the same source. The flotation process itself has a large number of variables, and some of these are difficult to control and even to measure. Because of this complexity, the process of finding new and improved flotation promoters, while grounded in chemical theory, relies on side-by-side comparisons of such compounds and known promoters, with all other conditions being held the same.